B-1/2 Steel G 1/2 Blanking Plug. Blanking plugs can protect against ingress of contamination, dirt, dust and grease in the tubing or pipes. This ensures that the pneumatic system and air is not compromised and also prevents equipment break down. Maintaining pressure in the system may be another reason blanking fittings are needed. Featuring a sealing ring the G thread connector offers a tight tube seal. Festo reliable pneumatic fittings offer you several benefits which are outlined below.